1. Field of Invention
The present invention relates to a chuck device for engagement with miniature tool bits.
2. Related Prior Art
In both U. S. Pat. Nos. 6,270,085 and 6,325,393, a chuck device is disclosed for engagement with tool bits. As shown in these patents, a tool bit 80 includes a shank and an annular groove 82 defined in the shank for engagement with a ball of the chuck device. However, such a configuration is not suitable for a miniature tool bit because such an annular groove seriously reduces cross-sectional area and therefore strength of such a miniature tool bit. Instead of an angular groove, a recess is defined in each of six corners of such a miniature tool bit. To match such a miniature tool bit, a new chuck device is needed.
It is the primary object of the present invention to provide a chuck device for engagement with miniature tool bits each including a number of corners each defining a recess.
The chuck device includes a socket, at least one ball, a first ring, an elastic element, a sleeve, a second ring and a spindle. The socket includes a chamber defined therein. The chamber includes a number of slots for receiving the corners of such a miniature tool bit. The socket includes at least one hole defined therein in communication with at least one of the corner-receiving slots. The at least one ball is received in the hole for engagement with the recess defined in at least one of the corners of the miniature tool bit. The first ring is mounted on the socket. The elastic element is mounted on the socket. The sleeve includes an annular groove defined in and an annular rib formed on an internal surface thereof. The sleeve is mounted on the socket. The elastic element is compressed between the ring and the annular rib, thus biasing the sleeve. The second ring is connected with the sleeve for engagement with the first ring, thus retaining the sleeve on the socket. The spindle is connected with the socket.
The socket may include two holes in communication with two of the slots. A ball is received in each of the holes.
The first ring may be a C-ring received in an annular groove defined in an external surface of the socket.
The second ring may be pressed into the sleeve.
The socket may include a second chamber defined therein for receiving the spindle.
The second chamber may be in communication with the first chamber. Thus, a pusher may be received in the first and second chambers for pushing the miniature tool bit. A second elastic element may be received in the second chamber for biasing the pusher.
The pusher may include a first recess defined therein for engagement with the miniature tool bit.
The pusher may include a second recess defined therein for engagement with the second elastic element.
The socket may include an annular shoulder formed between the first and second chambers. The pusher includes a third ring formed thereon for engagement with the annular shoulder, thus avoiding the pusher escaping from the second chamber.
The third ring may be a C-ring received in an annular groove defined in the pusher.
The spindle may include a first section received in the second chamber and a recess defined in the first section of the spindle for engagement with the second elastic element.